Fibrous tube



Patented Nov. 11, 1941 2,261,985 ,rmaous Tuna 'Albert E. Forster,Wilmington, DeL, asslgnor to Hercules Powder Company, Wilmingto n, Del

a corporation of Delaware No Drawing. Application January 11, 1940,Serial No. 3l3,377

s cut-um (cl. 138-76) This invention relates to fibrous tubes and moreparticularly to impregnated fibrous tubes suitable for use as temporarybore hole casings and as pipes for fluids.

An object of the present invention is to provide inexpensive impregnatedfibrous tubes which are light in weight and are relatively strong andrigid.

Another object to provide impregnated fibrous tubes which resistmoisture for a period 01' time and then are adapted to become saturatedand deteriorate.

A mrther object is to impregnate fibrous tubes with atemporarymoisture-proofing composition 3:315:15 readily adsorbed by the fibers ofthe Other and further objects will be obvious upon an understanding ofthe illustrative embodiment about to be described, or will be indicatedin the appended claims, and various advantages not referred to hereinwill occur to one skilled in the art upon employment of the invention inPractice.

- These objects, generally, are accomplished by impregnating tubesformed of paper, cardboard,

pulp board, or similar cellulcsic fibrous materials. preferably having athickness 01 between'.1 and .2 of an inch, and a diameter of about 3inches. The impregnating composition, which produces theforegoingdesired results, may consist of a substantiallypetroleum-hydrocarbon insoluble pine wood resin, or may comprise amixtureof the resin and bituminous or asphaltic material, such as tar,or, if desired, the composition may comprise a plastic-like reactionproduct of the resin and an oil, and bituminous or asphaltic material.Also, if desired, a mixture the reaction product and the coal tar may beployed.

The material which is characterized by the term substantiallypetroleum-hydrocarbon insoluble pine wood resin, herein and in theappended claims, is the resinous material which may be prepared frompine wood, preferably from stump pine wood, in the following manner. Thepine wood, which may or may not have been steamed to remove volatileconstituents such as turpentine and pine oil, may be extracted with acoal, tar hydrocarbon such as benzol or toluol, and the extract thenfreed of volatile constituents, leaving a residueconsistingofamixtureofwoodrodnandtheresin used in the presentcompositions. Extraction of this-mixture with a petrolemn hydrocarbonsuch as, for example, gasoline, dissolves and removes from the initialcoal tar the rosin. abietic acid, a resinous residue remains which islow in abietic acid.

Alternatively, a gasoline solution of the residue hydrocarbon extractmay be treated with furfural, and the two layers which form separated,in which case the petroleum-hydrocarbon insoluble pine wood resin isfound dissolved in the furfural from which it may be obtained byevaporation of the iurfural.

Another method of producing the resin comprises extracting rosin from'the wood by means of benzol amixture of gasoline and furfural. Thegasoline dissolves the rosin while the furiural dissolves the resin. Thesolvents are then separated and the resin is recovered by evaporation ofthe fur ural.

This resinous material, used in carrying out the present invention, ischaracterized by a dark red brown color, cherry red in solution, and bysubstantial insolubility in petroleum hydrocarbons, but it will varysomewhat in its specific characteristics such as acid number, meltingpoint, exact petroleum ether solubility, and content oi naphthaandtoluol insoluble material, depending upon the details of theextraction process utilized. This resin will meet or-nearly meet thefollowing specifications, namely, substantial insolubility in petroleumhydrocarbons, substantially complete solubility in alcohol, a methoxvcontent from about 3% to about 7.23% (usually from about 4% to about6%), an acid number in the range from about to about 110, and a dropmelting point in the range from about C. to about C.

The coal tar which is suitable in the composition may be a high boilingcoal tar oil or a coal tar pitch.

The oil used in making action product may be a semi-drying oil, suchasflsh oil or adrying oil, such-as linseedoil, which preferably can becooked to compatibility with the resin. Where fish oil hereinafter andin the claims, it is intended to include such semi-dryin or drying oilsgenerally known. If desired, action product, hexamethylenetetramine orformaldehyde is added to assist the partial conversion of the resin to agel.

The P s nt invention is not intended to be limited to specificproportions of ingredients. It has been found that an impregnatingcomposition consisting only 0! the substantially petroleum hydrocarboninsoluble pine wood resin is After separation of the rosin, high in andtreating the extracted rosin with I the plastic-like reis mentioned inpreparing the resuitable. This resin may be modified with coal tar. Forexample, for every ten parts of coal tar between about 1 part and about90 parts resin may be used. Where the reaction product of the resin witha drying or semi-drying oil is added to about parts coal tar, up toabout 40 parts resin, and between 10 and 200 parts reaction productcomprise the composition. The reaction product may vary in composition,between about 33% and 70% resin and the balance drying or semi-dryingoil to total 100%. A small amount of hexamethylenetetramine orformaldehyde is added to facilitate conversion of the resin.

The following examples illustrate compositions suitable for impregnatingfibrous cellulosic tubes to accomplish the objects of the presentinvention:

Materials (parts by weight) Examples I II III IV V VI Resinfl. 100 -4040 10 Goal tar oil 10 10 10 Coal tar pitch 90 Reaction product GF. 10Reaction product FF 10 Reaction product AF 200 Substantially troleumhydrocarbon in soluble pine wood resin GF, a fish oil p astic, 33%resin," partly converted toa gel with hexamethylenetetramine.

FF, 50% resin" with fish oil cooked to convertibility with formaldehydeAF, 70% resin" with fish oil cooked to compatibility.

The impregnating compositions may be pre-.

pared by heat the materials to provide a low melt having a viscosity tofacilitate penetration of the fibrous tubes. Preferably, theimpregnation of the tubes is carried out in a vessel maintained under apressure of about 70 pounds per square inch, by the addition of an inertgas, such as nitrogen, while maintaining the temperature of the meltbetween about 120 and 180 0., but preferably at about 165 C. Byimpregnating under pressure, the cellulosic fibers are not degraded bythe heat of the melt. The tubes thereafter may be removed from theimpregnating bath and permitted to drain and dry in a suitable manner.

If desired, the tubes may be coated, impregnated, or saturated bybrushing, coating or spraying the compositions thereon or dipping thetubes therein. The amount of material absorbed may be controlled toprovide the tubes with any desired degree of water resistance.

The tubes impregnated in the foregoing manner by using the compositionsdescribed herein are suitable where a semi-permanent or temporary tubingisv desired. For example, where temporary pipe lines for pumping waterare desired at locations such as swamp or marsh land, which are notreadily accessible by motor trucks, the tubes, by being light in weight,can be readily carried manually. After the pipe linesare no longerdesired, the tubes need not be recovered as would be the case-of moreexpensive metal pipe, but can be left at the location and upon be ingexposed to. rain and sun will deteriorate.

The. tubes, in accordance with the invention, are also suitable forlining bore holes used for explosive charges in seismic prospecting.Here again the tubes are readily brought on location, are sufllcientlystrong to keep the bore hole open to permit the desired number ofcharges to beexploded and can thereafter be abandoned and permitted todeteriorate without becoming a menace to tilling of the soil, or tonavigation in the event they are used for lining holes beneath thesurface of lakes or bays.

The tubes so impregnated may be of any suitable design. For example,tubes formed of spirally woundstrips may be used. The impregnatingcomposition serves to strengthen the joints of the strips and serves toprevent unravelling thereof.

It will be understood that the details and examples hereinbefore setforth are illustrative only and thattheinvention as broadly describedand claimed is in no way limited thereby.

What I claim and desire to protect by Letters mixture comprising coaltar and a material selected from the group consisting of a substantiallypetroleum-hydrocarbon insoluble pine wood resin, and reaction productsof said resin with a semi-drying oil.

3. A tube of the class described composed of fibrous cellulosic materialimpregnated with a substantially petroleum hydrocarbon insoluble pinewood resin.

4. A tube of the class described composed of fibrous cellulosic materialimpregnated with a mixture consisting of coal tar and a substantiallypetroleum-hydrocarbon insoluble pine wood resin.

5. A tube of the class described composed of fibrous cellulosic materialimpregnated with a mixture comprising coal tar, and a reaction productof a fish oil and a substantially petroleumhydrooarbon insoluble pinewood resin.

6. A tube of the class described composed of fibrous cellulosic materialimpregnated with a mixture consisting of ,a coal tar, a substantiallypetroleum-hydrocarbon insoluble pine wood resin, and a reaction productof said resin and a fish oil.

ALBERT E. FORS'IER.

DISCLAIMER 2,261,985.Alber E. Forster, Wilmington, Del. FIBROUS TUBE.Patent dated N ovemlier 11, 1941. Disclaimer filed May 11, 1943, by' theessignee, Herc'iles Powder C'ompany,

Hereb enters this disclaimer to-esmuch of claim 1 as will include asubstantially petrol'eumydrocarbon insoluble pinewood resin as theimpregnating material; and

to claim 3 in said patent..

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